KR20200082348A - Display device and image quality compensation method of the same - Google Patents

Abstract

A display device is disclosed. The display device includes: a display panel which receives image signals to display an image, and includes a first region having a first luminance and a second region having a second luminance lower than the first luminance; an image analysis unit which analyzes the image signals including first data to be provided to the first region and second data to be provided to the second region to determine whether or not the second region has a spot or whether or not a compensation margin for the second data exist; a first compensation unit which adjusts the second data to a value corresponding to a luminance value of the first data when the spot is recognized and the compensation margin exists; a second compensation unit which adjusts the first data to a value corresponding to a luminance value of the second data when the spot is recognized and the compensation margin does not exist; and a brightness control unit which increases the operating frequency of the pixels in the second region up to a predetermined ratio when the spot is recognized and the compensation margin does not exist.

Description

DISPLAY DEVICE AND IMAGE QUALITY COMPENSATION METHOD OF THE SAME

The present invention relates to a display device and a method for compensating the image quality thereof.

The flat panel display device is an electroluminescence display (ELD), field emission display device such as a liquid crystal display (LCD) or an organic light emitting diode display (OLED). Display, FED), plasma display panel (PDP), electrophoresis display (Electrophoresis Display, EPD) and the like.

On the other hand, as the display device is enlarged, a difference in physical characteristics of the panel of the display device may gradually occur, and as a result, some regions of the panel may have luminance characteristics different from those of the surroundings. In this case, it is necessary to perform the luminance characteristic to adjust the luminance characteristic of the partial region similarly to the surrounding regions.

An object of the present invention is to provide a display device and a method for compensating for the image quality thereof, which can improve display quality by compensating for deterioration in image quality in which stains on the display panel are recognized.

A display device according to an exemplary embodiment of the present invention is provided with image signals to display an image, and a display panel including a first region having a first luminance and a second region having a second luminance lower than the first luminance, The image signals including the first data to be provided in the first region and the second data to be provided in the second region are analyzed to determine whether the second region is uneven and whether the compensation margin is compensated for the second data. An image analysis unit, the first compensation unit to adjust the second data to a value corresponding to the luminance value of the first data when the stain is recognized and the compensation margin exists, the stain is recognized, and the compensation margin is When not present, the second compensation unit and the unevenness to adjust the first data to a value corresponding to the luminance value of the second data are recognized, and when the compensation margin is not present, the operating frequency of the pixels in the second area It includes a luminance control unit for increasing the predetermined ratio.

A method for compensating image quality of a display device according to an exemplary embodiment of the present invention includes: first data to be provided in a first region of a display panel having a first luminance and a second luminance of the display panel having a second luminance lower than the first luminance Analyzing image signals including second data to be provided in an area to determine whether the second area is uneven and whether to compensate for the second data, when the unevenness is recognized and the compensation margin exists, Adjusting the second data to a value corresponding to the luminance value of the first data, when the unevenness is recognized and the compensation margin does not exist, the first data corresponds to the luminance value of the second data And adjusting the operation frequency of the pixels in the second region by a predetermined ratio when the stain is recognized and the compensation margin is not present.

In the display device according to an exemplary embodiment of the present invention, the luminance of the second region of the display panel having the luminance lower than that of the first region of the display panel is increased to the luminance of the first region. Can be prevented. As a result, the deterioration of image quality in which the unevenness of the display panel is recognized is compensated, and the display quality can be improved.

1 is a block diagram of a display device according to an exemplary embodiment of the present invention.
FIG. 2 is a view showing a planar configuration of the display panel shown in FIG. 1.
3 is a block diagram of the compensation circuit shown in FIG. 1.
4 is a block diagram of the image analysis unit illustrated in FIG. 3.
5 to 7 are views for explaining the operation of the first and second comparison units shown in FIG. 4.
8 is a view for explaining the operation of the compensation determination unit shown in FIG. 4.
9 is a view for explaining the operation of the first compensation unit illustrated in FIG. 3.
10 and 11 are views for explaining the operation of the second compensation unit illustrated in FIG. 3.
12 is a view for explaining the operation of the luminance control unit shown in FIG. 3. FIG. 13 is a diagram illustrating a pulse width modulated signal shown in FIG. 3.
14 is a flowchart illustrating a method for compensating image quality of a display device according to an exemplary embodiment of the present invention.

Advantages and features of the present invention, and methods for achieving them will be clarified with reference to embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various different forms, and only these embodiments allow the disclosure of the present invention to be complete, and have ordinary knowledge in the art to which the present invention pertains. It is provided to fully inform the person of the scope of the invention, and the invention is only defined by the scope of the claims. The same reference numerals refer to the same components throughout the specification.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of a display device according to an exemplary embodiment of the present invention.

Referring to FIG. 1, the display device 100 according to an exemplary embodiment of the present invention may include a display panel 110, a timing controller 120, a gate driver 130, and a data driver 140.

For example, the display panel 110 may be a cathode ray tube (CRT), a liquid crystal display (LCD), a light emitting diode (LED), a plasma display panel (PDP), an organic LED (OLED), or a flexible display panel. However, it is not limited thereto. The display panel 110 may include a plurality of gate lines GL1 to GLm, a plurality of data lines DL1 to DLn, and a plurality of pixels PX. m and n are natural numbers.

The gate lines GL1 to GLm may extend in the first direction DR1 and be arranged in the second direction DR2 crossing the first direction DR1. The gate lines GL1 to GLm may be connected to the gate driver 130.

The data lines DL1 to DLn may extend in the second direction DR2 and be arranged in the first direction DR1. The data lines DL1 to DLn may be insulated from and cross the gate lines GL1 to GLm. The data lines DL1 to DLn may be connected to the data driver 140.

The pixels PX may be arranged in a matrix form to be connected to the gate lines GL1 to GLm and the data lines DL1 to DLn. The pixels PX may display red, green, or blue colors. However, the present invention is not limited thereto, and the pixels PX may further display various colors such as white, yellow, cyan, or magenta.

The timing controller 120 may be mounted on a printed circuit board (not shown) in the form of an integrated circuit chip and connected to the gate driver 130 and the data driver 140. The timing controller 120 may receive image signals RGB and a control signal CS from an external (eg, system board). The image signals RGB may be signals provided to the display panel 110 to display an image. The control signal CS may be a signal for controlling the operation of the display device 100.

The timing controller 120 may convert the data format of the image signals RGB to meet the interface specification with the data driver 140. The timing controller 120 may provide image data DATA converted from the data format of the image signals RGB to the data driver 140.

The timing controller 120 may include a compensation circuit 160. The compensation circuit 160 may compensate for the image signals RGB to compensate for the image quality of the display panel 110. In practice, image compensation signals that compensate for the image signals RGB may be converted into image data DATA by the timing controller 120 and output.

The compensation circuit 160 may determine whether or not the stain that may occur in the display panel 110 is visually recognized. When it is determined that the stain of the display panel 110 is recognized, the compensation circuit 160 may compensate for the image signals RGB so that the stain of the display panel 110 is not recognized. This operation will be described in detail below.

The timing controller 120 may generate a gate control signal GCS and a data control signal DCS in response to the control signal CS. The control signal CS may include a vertical synchronization signal, a horizontal synchronization signal, a data enable signal, and a main clock signal.

The gate control signal GCS may be a control signal for controlling the operation timing of the gate driver 130. The data control signal DCS may be a control signal for controlling the operation timing of the data driver 140. The timing controller 120 may provide a gate control signal GCS to the gate driver 130 and a data control signal DCS to the data driver 140.

The gate driver 130 may generate gate signals in response to the gate control signal GCS. The gate signals may be provided to the pixels PX through the gate lines GL1 to GLm. The gate signals may be sequentially provided to the pixels PX.

The data driver 140 may generate data voltages in analog form corresponding to the image data DATA in response to the data control signal DCS. The data voltages may be provided to the pixels PX through the data lines DL1 to DLn.

The gate driver 130 and the data driver 140 may be formed of a plurality of driving chips, mounted on a flexible printed circuit board, and connected to the display panel 110 by a tape carrier package (TCP) method. . However, the present invention is not limited thereto, and the gate driver 130 and the data driver 140 may be formed of a plurality of driving chips and mounted on the display panel 110 in a chip on glass (COG) method.

The timing controller 120 may analyze the image signals RGB to adjust the brightness (or output) of the panel 110. According to embodiments, the timing controller 120 may determine a duty ratio of a signal for adjusting an operation cycle (or operating frequency) of the pixels PX. Since the operation period of the pixels PX varies according to the duty ratio of the signal, accordingly, the overall brightness of the pixels PX may be adjusted. For example, the signal for adjusting the operation frequency of the pixels (hereinafter, the pixel operation signal) may be a data voltage supplied to a pixel or an operation voltage supplied to a pixel.

For example, when the image signals RGB are image signals RGB for displaying a dark image, the timing controller 120 reduces the overall brightness of the panel 110 by reducing the operating frequency of the pixels PX. When the image signals RGB are image signals RGB for displaying a bright image, the timing controller 120 increases the overall brightness of the panel 110 by increasing the operating frequency of the pixels PX. Can increase

The compensation circuit 160 may determine a duty ratio of a signal for adjusting the output period (or output frequency) of the pixels PX according to whether or not the stain of the display panel 110 is recognized. For example, the compensation circuit 160 may determine a duty ratio of a signal for adjusting the operating frequency of the pixels PX to match the luminance of the portion where the unevenness of the display panel 110 is displayed to the luminance of the peripheral portion. . This operation will be described in detail below.

FIG. 2 is a view showing a planar configuration of the display panel shown in FIG. 1. 3 is a block diagram of the compensation circuit shown in FIG. 1.

Referring to FIG. 2, the display panel 110 may include a first area A1 and a second area A2. The first region A1 may have a first luminance characteristic and the second region A2 may have a second luminance characteristic. In the present specification, the luminance characteristic refers to a characteristic (or relationship) between luminances displayed on the display panel for a given image signal (ie, voltage). According to embodiments, for the same voltage, the first luminance characteristic exhibits a higher luminance than the second luminance characteristic.

The display panel 110 may not have uniform luminance characteristics due to manufacturing process errors. For example, the transistors of the pixels PX are ideally all manufactured identically and have the same luminance characteristics, but due to process errors, luminance characteristics between the pixels PX may not be uniform.

Accordingly, even if the data voltage is the same, the luminance of the image displayed by the pixels PX in the first region A1 is higher than that of the image displayed by the pixels PX in the second region A2. Can be high In other words, in order to display an image of the same luminance in the second area A2 and the first area A1, the data voltage provided to the pixels PX of the second area A2 is the first area A1. It should be higher than the data voltage provided to the pixels PX. That is, the second region A2 may look like a stain.

The first area A1 may be a target area as a target area to compensate for luminance characteristics of the second area A2. As described above, in order to display an image of the same luminance in the second area A2 and the first area A1, the data voltage provided to the pixels PX of the second area A2 is the first area ( Since it must be higher than the data voltage provided to the pixels PX of A1), it is necessary to correct the data voltage provided to the pixels PX of the second region A2.

For example, although the first area A1 is shown to surround the second area A2, the size and position of the first area A1 and the second area A2 are not limited thereto. For example, the second area A2 may be disposed on side surfaces of the display panel 110.

The second region A2 having a lower luminance than the first region A1 may be recognized as unevenness according to the average luminance and luminance diversity of the image signals RGB. The condition in which the second region A2 is recognized as a stain will be described in detail below.

2 and 3, the compensation circuit 160 may include an image analysis unit 161, a first compensation unit 162, a second compensation unit 163, and a luminance control unit 164. The timing controller 120 may include a data conversion unit 121.

The image analysis unit 161 may receive image signals RGB and analyze the image signals RGB to determine whether the second region A2 is uneven. When the second area A2 is recognized as a stain, the image analysis unit 161 may provide the activation signal AS to the first and second compensation units 162 and 163 and the luminance control unit 164. When the second area A2 is not recognized as a stain, the image analysis unit 161 may provide the deactivation signal IAS to the first and second compensation units 162 and 163 and the luminance control unit 164.

The image signals RGB may include first data DAT1 to be provided in the first area A1 and second data DAT2 to be provided to the second area A2. The image analysis unit 161 may determine whether to compensate for the second data DAT2 using the image signals RGB. The operation of determining whether or not the compensation margin is described will be described in detail below.

The image analysis unit 161 may provide the first compensation signal CS1 to the first compensation unit 162 when a compensation margin for the second data DAT2 in the second area A2 exists. When there is no compensation margin for the second data DAT2, the image analysis unit 161 may provide the second compensation signal CS2 to the second compensation unit 163 and the luminance control unit 164.

The first and second compensation units 162 and 163 and the luminance control unit 164 may be activated in response to the activation signal AS. That is, the first and second compensation units 162 and 163 and the luminance control unit 164 may operate. The first and second compensation units 162 and 163 and the luminance control unit 164 may be deactivated in response to the deactivation signal IAS. That is, the first and second compensation units 162 and 163 and the luminance control unit 164 may not operate.

The activated first compensation unit 162 may receive image signals RGB. The activated first compensation unit 162 may compensate for the second data DAT2 of the image signal RGB to be provided in the second area A2 in response to the first compensation signal CS1. For example, the first compensation unit 162 may compensate by adjusting the second data DAT2 to a value corresponding to the luminance value of the first data DAT1. The first compensation unit 162 may provide the compensated image signals RGBc1 to the data conversion unit 121.

When the second data DAT2 is compensated with a value corresponding to the luminance value of the first data DAT1, the second luminance of the second area A2 may be increased to the first luminance of the first area A1. have. Therefore, the luminance of the second region A2 is matched to the luminance of the first region A1, and the difference in luminance between the first region A1 and the second region A2 may not be recognized. Matching in the present specification may mean a level at which the luminance difference between the first area A1 and the second area A2 is not recognized by the user.

The activated second compensation unit 163 may be provided with image signals RGB. The activated second compensation unit 163 converts the first data DAT1 of the image signal RGB to be provided to the first area A1 in response to the second compensation signal CS2 and the luminance of the second data DAT2. It can be compensated by adjusting the value corresponding to the value. The second compensation unit 163 may provide the compensated image signals RGBc2 to the data conversion unit 121.

When the first data DAT1 is compensated with a value corresponding to the luminance value of the second data DAT2, the first luminance of the first area A1 may fall to the second luminance of the second area A2. have. Therefore, the luminance of the first region A1 is matched to the luminance of the second region A2, and the difference in luminance between the first region A1 and the second region A2 may not be recognized. However, since the luminance of the first region A1 is lowered to the second luminance, the luminance of the display panel 110 may be lowered to the second luminance. The luminance of the lowered display panel 110 may be raised again by the luminance control unit 164.

The data converter 121 may convert the data formats of the image signals RGBc1 and RGBc2 compensated to meet the interface specification with the data driver 140 as an operation of the timing controller 120 described above. The data converter 121 may provide image data DATA with the data format converted to the data driver 140.

The luminance control unit 164 may receive image signals RGB and analyze the image signals RGB to generate a pixel operation signal. The luminance control unit 164 may determine the duty ratio of the pixel operation signal based on the luminance of the image signals RGB, and adjust the operating frequency of the pixels according to the determined duty ratio.

The activated luminance control unit 164 may increase the duty ratio of the pixel operation signal by a predetermined ratio in response to the second compensation signal CS2. For example, the luminance control unit 164 uses the first and second data DAT1 and DAT2 of the image signals RGB to increase the duty ratio of the pixel operation signal by a predetermined ratio ( G1) can be calculated. The operation of calculating the first gain G1 will be described in detail below.

The luminance control unit 164 may add and output the first gain G1 to the pixel operation signal based on the first gain G1. Since the pixels PX are driven by the pixel operation signal to which the first gain G1 is added, the luminance of the light outputted by the pixels PX may be generally increased by a predetermined ratio. That is, the luminance of the pixels PX may be generally increased by a predetermined ratio by the luminance control unit 164.

The first gain G1 may be determined as a value capable of raising the second luminance of the display panel 110 lowered by the second compensation unit 163 to the first luminance.

4 is a block diagram of the image analysis unit illustrated in FIG. 3. 5 to 7 are views for explaining the operation of the first and second comparison units shown in FIG. 4. 8 is a view for explaining the operation of the compensation determination unit shown in FIG. 4.

Referring to FIG. 4, the image analysis unit 161 may include a first comparison unit 1611, a second comparison unit 1612, and a compensation determination unit 1613. The first comparison unit 1611 and the second comparison unit 1612 may determine whether the second region A2 is uneven.

Referring to FIG. 5, it may be determined whether the second region A2 is uneven according to the average peak luminance (APL) and luminance complexity of the image signals RGB. The higher the average luminance of the image signals RGB, the higher the spot recognition, and the lower the average luminance of the image signals RGB, the lower the spot recognition.

As the average luminance of the image displayed on the display panel 110 is lower, the second region A2 having lower luminance may not be recognized as a stain. As the average luminance of the image is lower, since the first region A1, which is the peripheral region of the second region A2, may also have dark luminance, the probability that the second region A2 is perceived as a stain may be low.

As the average luminance of the image displayed on the display panel 110 is higher, the second region A2 having lower luminance may be recognized as a stain. As the average luminance of the image is higher, the first region A1, which is the peripheral region of the second region A2, may have high luminance, so the possibility that the second region A2 is perceived as stain may be high.

The luminance complexity may be increased as regions of the display panel 110 have various luminances. For example, if any 12 regions of the display panel 110 each have 12 different luminance values, the luminance diversity may be increased, and if all 12 regions have a single luminance value, that is, 1 If the dog has luminance values, luminance diversity may be lowered.

When luminance is changed in 12 regions of the display panel 110, the possibility of spotting in the second region A2 may be lowered. However, when the regions of 12 display a single luminance, that is, when the luminance does not change in the 12 regions, the second region A2 having different luminance may be recognized as a stain.

Therefore, as the luminance diversity is higher, the second region A2 may not be recognized as a stain, and as the luminance diversity is lower, the second region A2 may be recognized as a stain. For example, the luminance diversity of the image signals RGB may be based on the luminance standard deviation, but is not limited thereto, and the edge regions (regions or boundaries where the luminance value difference is greater than or equal to a reference value) of the image signals RGB are many It can be based on less.

According to the average luminance and luminance diversity of the image signals RGB, the spot recognition may be divided into a region having a low spot recognition, a region having a medium spot recognition, and a region having a high spot recognition. A region having low average luminance may be a region having low spot recognition. A region having high average luminance and high luminance diversity may be a region in which spot recognition is medium. A region having high average luminance and low luminance diversity may be a region having high spot recognition.

In an embodiment of the present invention, when the image signals RGB correspond to a region having high stain recognition, the second region A2 may be determined as a state that can be recognized as a stain.

4, 5, and 6, the first comparator 1611 receives image signals RGB and compares the average luminance of the image signals RGB with the first comparison value Ref1 Can. The first comparison unit 1611 may provide the operation signal DS to the second comparison unit 1612 when the average luminance of the image signals RGB is greater than the first comparison value Ref1. The second comparator 1612 may operate in response to the operation signal DS.

When the average luminance of the image signals RGB is less than or equal to the first comparison value Ref1, the first comparator 1611 first and second compensators 162 and 163 and the luminance controller (164). The first and second compensators 162 and 163 and the luminance controller 164 may not operate due to the deactivation signal IAS.

Since the average luminance of the image signals RGB is low and the second region A2 may not be perceived as unevenness, the first and second compensation units 162 and 163 and the luminance control unit 164 may prevent the compensation operation from being performed. May not work.

4, 5, and 7, the second comparator 1612 receives image signals RGB in response to the operation signal DS, and determines the luminance standard deviation of the image signals RGB. It can be compared with the second comparison value Ref2. The second comparator 1612 may output the activation signal AS when the luminance standard deviation of the image signals RGB is smaller than the second comparison value Ref2. As described above, the compensation operation may be performed by the first and second compensation units 162 and 163 and the luminance control unit 164 operating by the activation signal IA.

The second comparator 1612 may output an inactive signal IAS when the luminance standard deviation of the image signals RGB is greater than or equal to the second comparison value Ref2. The first and second compensators 162 and 163 and the luminance controller 164 may not operate due to the deactivation signal IAS.

The first and second compensation units 162 and 163 and the luminance control unit 164 may prevent the compensation operation from being performed because the second standard area A2 may not be recognized as unevenness because the luminance standard deviation of the image signals RGB is high. May not work.

As a result, when the average luminance of the image signals RGB is greater than the first reference value Ref1 and the luminance standard deviation of the image signals RGB is less than the second reference value Ref2, the first and second compensation units The compensation operation may be performed by the operation of (162,163) and the luminance control unit 164.

4 and 8, the relationship between the voltage and luminance of the first region A1 may be represented by a first gamma curve A1_GC, and the relationship between the voltage and luminance of the second region A2 may be It can be represented by 2 gamma curve (A2_GC). That is, the first gamma curve A1_GC represents the voltage-luminance characteristic of the first area A1, and the second gamma curve A2_GC represents the voltage-luminance characteristic of the second area A2. As described above, the first region A1 may be a region serving as a reference for compensating the luminance of the second region A2, and the first gamma curve A1_GC compensates for the second gamma curve A2_GC. It can be a standard for. For example, values (that is, compensation values) serving as a reference for compensating the second gamma curve A2_GC according to the first gamma curve A1_GC may be stored in advance. Can

The image signals RGB may include gradation values, and the gradation values may be substantially digital data values. The gradation values may be converted to analog voltages in the data driver 140 and provided to the pixels PX. Accordingly, the first and second data DAT2 of the image signals RGB may refer to a gradation value or voltage illustrated in FIG. 9.

The first and second data DAT1 and DAT2 may have values ranging from a minimum of 0 to a maximum of 255. That is, the first and second data DAT1 and DAT2 may have up to 256 gradation values. The luminance corresponding to 255 gray levels may be defined as the maximum luminance (Lmax). The voltage corresponding to 255 gray levels may be defined as the maximum voltage Vmax, but is not limited thereto, and the maximum voltage Vmax may exceed the voltage corresponding to 255 gray levels.

When the first data DAT1 is provided in the first area A1, luminance according to the first gamma curve A1_GC may be displayed. When the second data DAT2 is provided in the second area A2, luminance according to the second gamma curve A2_GC may be displayed.

Based on the luminance of the first and second gamma curves A1_GC and A2_GC, an area where the first gamma curve A1_GC and the second gamma curve A2_GC overlap each other may be defined as an overlapping area OA. . A region in which the first gamma curve A1_GC and the second gamma curve A2_GC do not overlap each other may be defined as a non-overlapping region NOA.

In FIG. 9, the overlapping region OA and the non-overlapping region NOA are defined according to whether the first gamma curve A1_GC and the second gamma curve A2_GC overlap in the vertical direction (ie, the luminance axis) in FIG. Can be. The voltage corresponding to the boundary between the overlapping region OA and the non-overlapping region NOA may be defined as the boundary voltage VB.

The compensation determining unit 1613 may receive image signals RGB and determine whether or not there is a compensation margin for the second data DAT2 (hereinafter, a compensation margin). Here, the compensation margin for the second data DAT2 means that the luminance of the image displayed by the second data DAT2 is provided to the second area A2, and the second data DAT2 is the first area A1. ) To mean the value of the voltage required to be equal to the luminance of the displayed image.

The compensation determining unit 1613 detects the positions of the luminance values of the first and second data DAT1 and DAT2 corresponding to the same voltage in the first and second gamma curves A1_GC and A2_GC, and the second data ( DAT2) can be determined whether or not the compensation margin.

When the luminance values of the first and second data DAT1 and DAT2 corresponding to the same voltage are disposed in the overlapping area OA, the compensation determining unit 1613 may determine that a compensation margin exists. For example, since the luminance values of the first and second data DAT1 and DAT2 corresponding to the first identical voltage VD1 are disposed in the overlapping area OA, the compensation determining unit 1613 may include the second data ( It can be determined that a compensation margin for DAT2) exists.

When the luminance values of the first and second data DAT1 and DAT2 corresponding to the same voltage are respectively disposed in the non-overlapping area NOA and the overlapping area OA, the compensation determining unit 1613 has no compensation margin. It can be determined to exist. For example, the luminance value of the first data DAT1 corresponding to the second identical voltage VD2 is disposed in the non-overlapping area NOA, and the second data DAT2 corresponding to the second identical voltage VD2. Since the luminance value of is disposed in the overlapping area OA, the compensation determining unit 1613 may determine that the compensation margin for the second data DAT2 does not exist.

Alternatively, the compensation determining unit 1613 may determine whether the compensation margin is based on the position of the same voltage based on the boundary voltage VB. For example, the compensation determining unit 1613 determines that a compensation margin exists when the same voltage is disposed in a range of a voltage level lower than or equal to the boundary voltage VB, such as the first same voltage VD1. Can. The compensation determining unit 1613 may determine that the compensation margin does not exist when the same voltage is disposed in a range of a voltage level greater than the boundary voltage VB, such as the second identical voltage VD2.

In order to more easily perform the compensation margin discrimination operation, the compensation determining unit 1613 detects a high voltage region higher than the first reference voltage Vref in a voltage range corresponding to the first and second data DAT1 and DAT2. Can. The first reference voltage Vref may have a voltage level lower than the boundary voltage VB.

Compensation margin using the first and second data DAT1 and DAT2 corresponding to the high voltage region without using all of the first and second data DAT1 and DAT2 corresponding to the 0 to maximum voltage Vmax If it is determined, the operation of determining the compensation margin can be more easily performed.

9 is a view for explaining the operation of the first compensation unit illustrated in FIG. 3.

For convenience of description, FIG. 10 shows a first gamma curve A1_GC of the first area A1 and a second gamma curve A2_GC of the second area A2. According to the needs of the description, the first and second regions A1 and A2 illustrated in FIG. 2 and the first compensation unit 162 illustrated in FIG. 4 will be described together.

Referring to FIG. 9, since luminance values L1 and L2 of the first and second data DAT1 and DAT2 corresponding to the first voltage V1 are disposed in the overlapping area OA, a compensation margin exists Can. At the first voltage V1, the first data DAT1 may have a first luminance value L1, and the second data DAT2 may have a second luminance value L2 lower than the first luminance value L1. have.

The first compensation unit 162 increases the second data DAT2 of the second area A2 to a voltage value of the second data DAT2 corresponding to the first luminance value L1 of the first data DAT1. Can be adjusted. For example, the first compensator 162 may replace the first voltage V1 of the second data DAT2 with the second data DAT2 corresponding to the first luminance value L1 of the first data DAT1. It can be changed to the second voltage V2. Accordingly, the gradation value of the second data DAT2 may be adjusted upward from the gradation value corresponding to the first voltage V1 to the gradation value corresponding to the second voltage V2.

The second luminance of the second area A2 is increased to the first luminance of the first area A1 so that the first data DAT1 and the second data DAT2 have the same first luminance value L1. . The luminance of the second region A2 is matched to the luminance of the first region A1, so that the difference in luminance between the first region A1 and the second region A2 may not be recognized.

10 and 11 are views for explaining the operation of the second compensation unit illustrated in FIG. 3.

For convenience of description, FIGS. 10 and 11 show a first gamma curve A1_GC of the first area A1 and a second gamma curve A2_GC of the second area A2. According to the needs of the description, the first and second regions A1 and A2 illustrated in FIG. 3 and the second compensation unit 163 illustrated in FIG. 4 will be described together.

Referring to FIG. 10, luminance values L1_1 and L2_1 of the first and second data DAT1 and DAT2 corresponding to the first voltage V1_1 are in the non-overlapping region OA and the overlapping region OA. Since each is disposed, a compensation margin may not exist. At the first voltage V1_1, the first data DAT1 may have a first luminance value L1_1, and the second data DAT2 may have a second luminance value L2_1 lower than the first luminance value L1_1. have.

In order to adjust the second data DAT2 of the second area A2 to the voltage value of the second data DAT2 corresponding to the first luminance value L1_1 of the first data DAT1, the second data DAT2 The first voltage V1_1 of should rise to the second voltage V2_2. However, since the second voltage V2_2 is larger than the maximum voltage Vmax, the first voltage V1_1 cannot be raised to the second voltage V2_2. As described above, when the compensation margin is insufficient due to the absence of the compensation margin, the second compensation unit 163 may adjust the first data DAT1.

Referring to FIG. 11, the second compensation unit 163 corresponds to the first data DAT1 corresponding to the second luminance value L2_1 of the second data DAT2 and the first data DAT1 of the first area A1. ). For example, the second compensation unit 163 converts the first voltage V1_1 of the first data DAT1 to the third voltage V3 corresponding to the second luminance value L2_1 of the second data DAT2. You can change it. Accordingly, the gradation value of the first data DAT1 may be adjusted downward from the gradation value corresponding to the first voltage V1_1 to the gradation value corresponding to the third voltage V3.

The first luminance of the first area A1 is lowered to the second luminance of the second area A2 so that the first data DAT1 and the second data DAT2 have the same second luminance value L2_1. have. The luminance of the first region A1 is matched to the luminance of the second region A2, so that the difference in luminance between the first region A1 and the second region A2 may not be recognized.

However, in this case, the luminance of the first region A1 is lowered to the second luminance, and the first and second regions A1 and A2 may have the second luminance. Therefore, the luminance of the display panel 110 may be lowered to the second luminance. The luminance of the lowered display panel 110 may be raised again by the luminance control unit 164.

12 is a view for explaining the operation of the luminance control unit shown in FIG. 3. FIG. 13 is a diagram illustrating a pulse width modulated signal shown in FIG. 3.

For convenience of description, FIG. 12 shows a first gamma curve A1_GC of the first area A1 and a second gamma curve A2_GC of the second area A2. According to the needs of the description, the first and second regions A1 and A2 illustrated in FIG. 2 and the luminance control unit 164 illustrated in FIG. 3 will be described together.

12 and 13, the luminance control unit 164 may increase the duty ratio of the pixel operation signal POS at a predetermined ratio. For example, the luminance control unit 164 may generate the first gain G1 calculated by dividing the first luminance value L1_1 by the second luminance value L2_1. The first gain G1 may be an increase ratio of the duty ratio of the pixel operation signal POS.

As described above, the first luminance value L1_1 may be the luminance value of the first data DAT1 before compensation. Since the first luminance value L1_1 is higher than the second luminance value L2_1, a value obtained by dividing the first luminance value L1_1 by the second luminance value L2_1 may be greater than 1.

The first gain G1 may be added to the pixel operation signal POS. Accordingly, the pulse width of the pixel operation signal POS may be increased from the first period PD1 to the second period PD2 by the luminance control unit 164 and output.

Since the operating frequency of the pixels PX is determined by the pixel operating signal POS, the luminance of the light generated in the pixels PX may be generally increased by the first gain G1. As the overall luminance of the pixels PX increases, the second luminance values L2_1 of the first and second data DAT1 and DAT2 may be increased to the first luminance value L1_1. Therefore, the luminance of the first and second regions A1 and A2 may be increased to the first luminance of the first region A1 before compensation.

According to the operation of the compensation circuit 160 described above, the luminance difference between the first and second regions A1 and A2 may be removed so that the unevenness of the second region A2 may not be recognized. Therefore, the display quality of the display device 100 can be improved.

14 is a flowchart illustrating a method for compensating image quality of a display device according to an exemplary embodiment of the present invention.

Referring to FIG. 14, in step S110, first data DAT1 to be provided in the first area A1 of the display panel 110 and second to be provided in a second area A2 of the display panel 110 The image signals RGB including the data DAT2 may be analyzed.

In step S120, the image signals RGB are analyzed to determine whether the second region A2 is uneven. As described above, when the average luminance is less than or equal to the first comparison value Ref1 or when the luminance standard deviation is greater than or equal to the second comparison value Ref2, the second area A2 is not recognized as a stain. The picture quality compensation method may end.

When the average luminance is greater than the first comparison value Ref1 and the luminance standard deviation is less than the second comparison value Ref2, the process proceeds to step S130, and the compensation margin for the second data DAT2 in step S130 This can be confirmed.

In step S140, whether a compensation margin is determined may be determined. As described above, luminance values of the first and second data DAT1 and DAT2 corresponding to the same voltage are arranged in the overlapping region OA of the first gamma curve A1_GC and the second gamma curve A2_GC. When it can be, it can be determined that a compensation margin exists. The luminance values of the first and second data DAT1 and DAT2 corresponding to the same voltage are non-overlapping regions NOA and overlapping regions OA of the first gamma curve A1_GC and the second gamma curve A2_GC. When each is placed in, it may be determined that the compensation margin does not exist.

If there is a compensation margin, the process proceeds to step S150, and in step S150, as the first compensation operation, the second data DAT2 of the second area A2 corresponds to the luminance value of the first data DAT1. It can be adjusted to a corresponding value. Therefore, the second luminance of the second region A2 may be increased to the first luminance.

If the compensation margin does not exist, the process proceeds to step S160, and in step S160, as the second compensation operation, the first data DAT1 of the first area A1 is the luminance value of the second data DAT2. It can be adjusted to a value corresponding to. Therefore, the first luminance of the first region A1 may be lowered to the second luminance.

In step S170, the operating frequency of the pixels PX may be increased. As described above, when the duty ratio of the pixel operation signal is increased by a predetermined ratio, the operation frequency of the pixels PX may be increased. The rising ratio may be calculated by dividing the luminance value of the first data DAT1 by the luminance value of the second data DAT2.

The luminance difference between the first and second regions A1 and A2 may be removed by the method of compensating the image quality of the display device 100 such that unevenness of the second region A2 may not be recognized.

Although described with reference to the above embodiments, those skilled in the art understand that various modifications and changes can be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. Will be able to. In addition, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, and all technical spirit within the scope of the following claims and equivalents thereof should be interpreted as being included in the scope of the present invention. .

100: display device 110: display panel
120: timing controller 130: gate driver
140: data driver 160: compensation circuit
161: image analysis unit 162: first compensation unit
163: second compensation unit 164: luminance control unit
1611: first comparison unit 1612: second comparison unit
1613: compensation decision unit

Claims (17)

A display panel receiving an image signal to display an image, and including a first region having a first luminance and a second region having a second luminance lower than the first luminance;
The image signals including the first data to be provided in the first region and the second data to be provided in the second region are analyzed to determine whether the second region is uneven and whether the compensation margin is compensated for the second data. A video analysis unit;
A first compensation unit configured to adjust the second data to a value corresponding to a luminance value of the first data when the unevenness is recognized and the compensation margin exists;
A second compensation unit that adjusts the first data to a value corresponding to a luminance value of the second data when the unevenness is recognized and the compensation margin does not exist; And
And a luminance control unit that increases the operating frequency of the pixels in the second region by a predetermined ratio when the unevenness is recognized and the compensation margin does not exist. According to claim 1,
The image analysis unit,
A first comparator comparing the average luminance of the video signals with a first comparison value;
A second comparison unit comparing the standard deviation of luminance of the image signals with a second comparison value according to the comparison result of the first comparison unit to determine whether or not the stain is detected; And
In the first gamma curve indicating the relationship between the voltage and luminance in the first region and the second gamma curve indicating the relationship between the voltage and luminance in the second region, the first and second data corresponding to the same voltage And a compensation determining unit that detects the position of the luminance values and determines whether the compensation margin exists. According to claim 2,
When the average luminance is larger than the first comparison value, the second comparison unit compares the luminance standard deviation and the second comparison value,
When the luminance standard deviation is smaller than the second comparison value, the second comparison unit displays the unevenness as a cognitive state. The method of claim 3,
The first and second comparators may include the first and second compensators when the average luminance is less than or equal to the first comparison value, or when the luminance standard deviation is greater than or equal to the second comparison value. A display device that deactivates the luminance control unit. According to claim 2,
The compensation determining unit determines that the compensation margin exists when the luminance values of the first and second data are disposed in an overlapping region of the first gamma curve and the second gamma curve based on the luminance. When the luminance values of the first and second data are respectively disposed in the non-overlapping region and the overlapping region of the first gamma curve and the second gamma curve based on the luminance, the compensation margin does not exist. Display device to be determined as. The method of claim 5,
The compensation determining unit determines whether the compensation margin is detected by detecting a high voltage region higher than a first reference voltage in a voltage range corresponding to the first and second data, and the first reference voltage is the overlapping region and the ratio A display device having a voltage level lower than a boundary voltage corresponding to a boundary between overlapping regions. According to claim 1,
The first compensation unit adjusts the second data upward to a voltage value of the second data corresponding to the luminance value of the first data. According to claim 1,
The second compensation unit adjusts the first data downward to a voltage value of the first data corresponding to the luminance value of the second data. The method of claim 8,
The luminance control unit increases the duty ratio of the pixel operation signal that controls the operation frequency of the pixels in the second region by a predetermined ratio. The method of claim 9,
The predetermined ratio is calculated by dividing the luminance value of the first data by the luminance value of the second data, and has a value greater than one. By analyzing image signals including first data to be provided in a first region of the display panel having a first luminance and second data to be provided to a second region of the display panel having a second luminance lower than the first luminance, Determining whether the second region is uneven and whether the second data is compensated;
Adjusting the second data to a value corresponding to a luminance value of the first data when the unevenness is recognized and the compensation margin exists;
Adjusting the first data to a value corresponding to a luminance value of the second data when the unevenness is recognized and the compensation margin does not exist; And
And if the unevenness is recognized and the compensation margin is absent, increasing the operating frequency of the pixels in the second area by a predetermined ratio. The method of claim 11,
Determining whether the stain and whether the compensation margin,
Comparing the average luminance of the video signals with a first comparison value;
Determining whether the stain is by comparing the standard deviation of luminance of the image signals with a second comparison value according to the comparison result; And
In the first gamma curve indicating the relationship between the voltage and luminance of the first region and the second gamma curve indicating the relationship between the voltage and luminance of the second region, the first and second data corresponding to the same voltage And determining whether the compensation margin exists by detecting a position of luminance values. The method of claim 12,
The determining whether the spot is a stain may include determining the spot as a cognitive state when the average luminance is greater than the first comparison value and the luminance standard deviation is less than the second comparison value. How to compensate for image quality. The method of claim 12,
The step of determining whether the compensation margin exists,
Determining that the compensation margin exists when the luminance values of the first and second data are arranged in an overlapping region of the first gamma curve and the second gamma curve based on the luminance; And
When the luminance values of the first and second data are respectively disposed in the non-overlapping region and the overlapping region of the first gamma curve and the second gamma curve based on the luminance, the compensation margin does not exist. Comprising the step of determining that the image quality compensation method of the display device. The method of claim 11,
The second data is the image data compensation method of the display device is adjusted upward to the voltage value of the second data corresponding to the luminance value of the first data. The method of claim 11,
The first data is the image data compensation method of the display device is adjusted down to the voltage value of the first data corresponding to the luminance value of the second data. The method of claim 16,
Controlling the operating frequency of the pixels in the second region includes increasing the duty ratio of the pixel operating signal for controlling the operating frequency of the pixels by a predetermined ratio,
The predetermined ratio is calculated by dividing the luminance value of the first data by the luminance value of the second data, and the image quality compensation method of the display device having a value greater than 1.

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